中文摘要：

研究了光波在没有光子带隙的三角晶格型光子晶体多模波导中的传播特性.利用等效折射率法,将该结构等效为三层平板介质波导,基于自映像原理,数值分析和模拟了其多模干涉效应.研究结果表明,由于全内反射和分布式布拉格反射的联合效应,光场类似于传统波导模式,能高效地传输;随着填充率的增大,高透射区域将向波长减小的方向移动,带宽和透射率也随之增加,研究结果为实际应用中选择适当的填充率提供了理论依据.

英文摘要：

The properties of the propagating field in multimode photonic crystal waveguides exhibiting no photonic band gaps with triangular lattices are investigated.By the effective refractive index method,these structures are regarded as three layer planar dielectric waveguides.And the multimode interference effect is numerically analyzed and simulated based on the self-imaging principle.The results show that the field can propagates effectively and resembles index-guided mode due to the combination of total internal reflection and distribution Bragg reflection.High transmission region shifts toward the shorter wavelength region,the bandwidth and the transmissivity increase with the increase of filling ratio,which provides a theoretical reference for selecting an appropriate filling ratio in practical applications.